Socket structure for the ball of a ball point pen refill

ABSTRACT

A socket structure for a ball point refill, which comprises a ball made of corundum and arranged inside an outer supporting shell provided in its interior with a compound bearing consisting of a backing shell having a hardness exceeding 800 kg/sq.mm Vickers and an inner lining facing the ball and having a hardness of less than 200 kg/sq.mm Vickers.

United States Patent [1 1 Herrnring [451 Sept. 24, 1974 SOCKET STRUCTUREFOR THE BALL OF A BALL POINT PEN REFILL [75] Inventor: Heinz GiintherHerrnring,

Alveslohe, Germany [73] Assignee: Montblanc-Simplo GmbI-I,

Hamburg, Germany [22] Filed: June 4, 1973 [21] Appl. No.: 366,855

[52] U.S. CI. 401/216 [51] Int. Cl B43k 7/10 [58] Field of Search401/216 [56] References Cited FOREIGN PATENTS OR APPLICATIONS 1,108,4008/1955 France 401/216 849,432 8/1960 Great Britain 40l/2l6 PrimaryExaminerLawrence Charles Attorney, Agent, or Firm--Walter Becker [5 7]ABSTRACT 4 Claims, 1 Drawing Figure I SOCKET STRUCTURE FOR THE BALL OF ABALL POINT PEN REFILL The invention relates to a socket for the ball ofa ball point pen refill comprising a multi-layer bearing socket havingan outer supporting shell consisting of a high strength material havinga high yield point in conjunction with an inner electrolytically orchemically deposited bearing liner consisting of chromium, nickel or analloy containing one of these metals and having a hardness exceeding 600kg/sq.mm Vickers.

Sockets of this kind have in the past given a satisfactory account ofthemselves. However, in the meantime metal compositions have becomeknown which permit the quality and wearing properties of the writingpoints of ball point pen refills to be even further improved.

It is therefore the object of the present invention to provide a writingpoint for a ball point pen refill which excels by its quality as awriting point and by its long useful life.

According to the invention this is achieved by providing a ball made ofcorundum contained in a compound bearing inside an external supportingshell, said compound bearing comprising a backing shell exceeding 800kg/sq.mm Vickers in hardness, whereas an inner lining facing the ball issofter than 200 kg/sq.mm Vickers.

In a preferred embodiment of the invention the external supporting shellwhich exceeds the ball in size is provided with an electro-depositednickel-tin layer which serves as a backing shell upon which a soft layerof silver is deposited to provide the inner lining.

The combination of the proposed ball with a compound bearing firstlyensures excellent dimensional stability throughout the life of the pointof the refill. On the other hand, the soft inner lining gives a softwriting touch.

Other details and features of the invention will become apparent fromthe following specification in connection with the accompanying Drawingillustrating a longitudinal section through the point according to theinvention of a ball point pen refill.

The socket for the ball 1 of a ball point pen refill comprisessubstantially an outer supporting shell 2, a backing bearing shell 3 andan inner lining shell 4. The material used for the inner shell 4 shouldhave a hardness of less than 200 kg/sq mm Vickers, preferably between 80and 120 kg/sq mm Vickers. The outer supporting shell 2 may be made of asubstance selected from the group consisting of chromium, nickel, and analloy containing at least one of the metals chromium and nickel andhaving a hardness in excess of 600 sq. mm Vickers. Such alloys may e.g.,be:

a. A chromium-iron alloy having from 10 to 20 percent by weight of ironand the remainder chromium.

b. A chromium-tungsten alloy having from 30 to 40 percent by weight oftungsten and the remainder chromium.

c. A nickel-chromium alloy having from 0.1-5 percent by weight ofchromium and the remainder nickel.

d. A tin-nickel alloy having from to 70 percent by weight of tin and theremainder nickel.

e. A nickel-aluminum oxide alloy having from 0. l-lO percent by volumeof A1 0 and the remainder nickel.

f. A nickel silicon carbide alloy having from l-50 percent by volume ofsilicon carbide and the remainder nickel.

It is, of course, to be understood that the above alloys may have minornegligible impurifications.

The backing bearing shell 3 is applied to the supporting shell 2, amaterial being used for shell 3 which has a hardness in excess of 600kg/sq. mm Vickers, when a single phase smooth hard layer is involved.When a multi-phase layer is involved, the hardest phase has a hardnessin excess of 1,000 kg/sq. mm Vickers. To this end, a nickel-tin layer iselectro-deposited onto the interior of the supporting shell 2. A largenumber of blanks for the points of ball point pen refills are thustreated in this way simultaneously. They are inserted from below intothe upper part of a holder. The individual holes in the upper part forthe reception of the points are fitted with sealing rings. This upperpart contains a heating chamber through which all the inserted pointspass. The heating chamber is connected by two pipes to a heat source.Principally this will be a source of hot steam.

A bottom part which contains a hole for the reception of each point isnow attached to the upper part. Each hole is open at its bottom endwhich has a reduced diameter. This end may also be a convergent cone.Seals between the points on the one hand and the upper and lower partson the other hand ensure that the assembly formed by the upper and lowerparts can be immersed in a bath without causing the exteriors of thepoints to be wetted.

For performing the electro-deposition the assembly is suspended in abath and vertically oscillated, preferably in the axial direction of thepoints. A bearing shell 3 will thus be deposited inside the outersupporting shell.

In order even further to improve the properties of the socket in theball point pen refill the invention further proposes to deposit on thehard film of the backing shell 3 a further soft lining having a hardnessof less than 200 kg/sq. mm. This softer layer consists of silver andimproves the running-in properties besides lengthening the life of thebearing. For this purpose a silver layer is selected which is free fromhardening additives, for instance free from antimony, and which isdeposited from a silver bath containing cyanide potassium hydroxide. Thesame method may be employed as that above described for applying thebacking shell 3.

The finished ball point, into which the ball 1 has been inserted canfinally be subjected to a thermal treatment in vacuo or in a protective,i.e., inert atmosphere. This post thermal treatment consists in a heattreatment for an hour in a vacuum or in an inert atmosphere at atemperature of from 200 to 500 centigrades, preferably at a temperatureof from 250-300 centigrades. The thermal treatment improves the bondbetween the several layers by fusion. The properties of the bearing maythus be further improved. However, when the ball 1 is located bypinching the edges of the shells, allowance must be made for thecontraction caused by the thermal treatment. The ball 1 must thereforebe inserted prior to the heat treatment with a slightly greaterclearance.

It is, of course, to be understood, that the present invention is, by nomeans, limited to the specific showing in the drawing, but alsocomprises any modification within the scope of the appended claims.

What I claim is:

1. For use in connection with a ball point refill writing instrument,the combination of: a multi-layer bearing socket having an outersupporting shell comprising a substance selected from the groupconsisting of chromium, nickel, and an alloy containing at least one ofthe metals chromium and nickel and having a hardness exceeding 600kg/sq.mm Vickers; a ball made of corundum and arranged inside said outersupporting shell; a compound bearing arranged on the inside of saidouter supporting shell and comprising both a backing shell having ahardness exceeding 800 kg/sq.rnm Vickers; and also an inner liningadjacent to and directly facing said ball and having a hardness of lessthan 200 kg/sq.mm Vickers.

2. A combination according to claim 1, in which the external supportingshell is of slightly greater dimensions than said ball and is providedwith an electrodeposited nickel-tin layer forming said backing shell andwith a soft silver film deposited on said backing shell and forming saidinner bearing lining directly for said ball.

3. A combination according to claim 1, in which said outer supportingshell consists of a heterogeneous aluminum multi-component bronzepredominantly of copper.

4. In a method of treating a ball point refill having: a multi-layerbearing socket with an outer supporting shell comprising a substanceselected from the group consisting of chromium, nickel and an alloycontaining at least one of the metals, chromium and nickel, and having ahardness exceeding 600 kg/sq.mm Vickers, a ball made of corundum andarranged inside said outer supporting shell, and comprising a backingshell having a hardness exceeding 800 kg/sq.mm Vickers, and an innerlining in the form of a soft silver film adjacent to and facing saidball and having a hardness of less than 200 kg/sqmm Vickers, whichincludes the step improvement of: subjecting said ball point refill to aheat treatment so as to create both a good bond between the severalshells and an increase in the hardness of said supporting shell bydiffusion, and also a reduction in the hardness of said silver film.

1. For use in connection with a ball point refill writing instrument,the combination of: a multi-layer bearing socket having an outersupporting shell comprising a substance selected from the groupconsisting of chromium, nickel, and an alloy containing at least one ofthe metals chromium and nickel and having a hardness exceeding 600kg/sq.mm Vickers; a ball made of corundum and arranged inside said outersupporting shell; a compound bearing arranged on the inside of saidouter supporting shell And comprising both a backing shell having ahardness exceeding 800 kg/sq.mm Vickers; and also an inner liningadjacent to and directly facing said ball and having a hardness of lessthan 200 kg/sq.mm Vickers.
 2. A combination according to claim 1, inwhich the external supporting shell is of slightly greater dimensionsthan said ball and is provided with an electro-deposited nickel-tinlayer forming said backing shell and with a soft silver film depositedon said backing shell and forming said inner bearing lining directly forsaid ball.
 3. A combination according to claim 1, in which said outersupporting shell consists of a heterogeneous aluminum multi-componentbronze predominantly of copper.
 4. In a method of treating a ball pointrefill having: a multi-layer bearing socket with an outer supportingshell comprising a substance selected from the group consisting ofchromium, nickel and an alloy containing at least one of the metals,chromium and nickel, and having a hardness exceeding 600 kg/sq.mmVickers, a ball made of corundum and arranged inside said outersupporting shell, and comprising a backing shell having a hardnessexceeding 800 kg/sq.mm Vickers, and an inner lining in the form of asoft silver film adjacent to and facing said ball and having a hardnessof less than 200 kg/sq.mm Vickers, which includes the step improvementof: subjecting said ball point refill to a heat treatment so as tocreate both a good bond between the several shells and an increase inthe hardness of said supporting shell by diffusion, and also a reductionin the hardness of said silver film.